This invention relates to a rail car center plate, and more particularly to a low friction, high wear center plate assembly.
A railroad car is typically mounted on a truck using a center plate assembly consisting of a cylindrical cast center plate, having a vertical side wall and a planar bottom, which rides in a cast bowl-shaped depression in the truck. To prevent one cast part from wearing on the second cast part, a steel wear plate is interposed between the center plate and the bowl. The wear plate is lubricated to further reduce friction. For a rail car traveling the average 100,000 miles a year, the wear plate must be relubricated every 2-3 months.
An alternative to the steel wear plate for reducing friction is a plastic cap which is placed over the center plate. However, both sides of the plastic cap are exposed to cast metal and thus the plastic wears quickly.
Railroads increasingly employ multiple unit articulated cars in which the ends of adjacent cars are carried on a common truck bolster located between the two units. With articulated cars consideration must also be given to the truck turning moment, since center plate binding caused by side loads is a suspected cause of derailment in articulated cars. European-type spherical bearings cannot be used to reduce the effect of side loads because of the increased rocking stability requirements necessitated by the height and weight of American double-stack freight cars.
What is still needed is a center plate bearing assembly that will reduce center plate bearing friction, reduce bearing wear, and reduce bearing maintenance.